X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/18c831dcd0ae4d660c70ccac69d27ed2a97851be..d04c0e00da3a27693bbf9cc4f2d5c88e56d80f20:/mem/alloc.c

diff --git a/mem/alloc.c b/mem/alloc.c
index e71ead4..8a62617 100644
--- a/mem/alloc.c
+++ b/mem/alloc.c
@@ -41,23 +41,37 @@
 
 /*----- Functions and macros ----------------------------------------------*/
 
-/* --- @x_alloc@ --- *
+/* --- @x_alloc@, @x_allocn@ --- *
  *
  * Arguments:	@arena *a@ = pointer to underlying arena
- *		@size_t sz@ = size of block to allocate
+ *		@size_t n@ = number of elements to allocate (for @x_allocv@)
+ *		@size_t sz@ = size of elements to allocate
  *
  * Returns:	Pointer to allocated block.
  *
- * Use:		Allocates memory.  If there's not enough memory, the
- *		exception @EXC_NOMEM@ is thrown.
+ * Use:		The @x_allocn@ function allocates memory for @n@ elements of
+ *		@sz@ bytes each (or, perhaps, %%\emph{vice versa}).  The
+ *		@x_alloc@ function is the same, but with @n@ fixed equal
+ *		to 1.  If there's not enough memory, the exception
+ *		@EXC_NOMEM@ is thrown.
  */
 
 void *x_alloc(arena *a, size_t sz)
 {
-  void *p = A_ALLOC(a, sz);
-  if (!p)
-    THROW(EXC_NOMEM);
-  return (p);
+  void *p;
+
+  p = A_ALLOC(a, sz);
+    if (!p) THROW(EXC_NOMEM);
+    else return (p);
+}
+
+void *x_allocv(arena *a, size_t n, size_t sz)
+{
+  void *p;
+
+  p = A_ALLOCV(a, n, sz);
+    if (!p) THROW(EXC_NOMEM);
+    else return (p);
 }
 
 /* --- @x_strdup@ --- *
@@ -74,32 +88,48 @@ void *x_alloc(arena *a, size_t sz)
 
 char *x_strdup(arena *a, const char *s)
 {
-  size_t sz = strlen(s) + 1;
-  char *p = x_alloc(a, sz);
-  memcpy(p, s, sz);
+  char *p; size_t sz;
+
+  sz = strlen(s) + 1; p = x_alloc(a, sz); memcpy(p, s, sz);
   return (p);
 }
 
-/* --- @x_realloc@ --- *
+/* --- @x_realloc@, @x_reallocv@ --- *
  *
  * Arguments:	@arena *a@ = pointer to underlying arena
  *		@void *p@ = pointer to a block of memory
- *		@size_t sz@ = new size desired for the block
- *		@size_t osz@ = size of the old block
+ *		@size_t n@ = new number of elements (for @x_reallocv@)
+ *		@size_t on@ = old  number of elements (for @x_reallocv@)
+ *		@size_t sz@ = size of elements (for @x_reallocv@) or new
+ *			block size (for @x_realloc@)
+ *		@size_t osz@ = size of the old block (for @x_realloc@)
  *
  * Returns:	Pointer to the resized memory block (which is almost
  *		certainly not in the same place any more).
  *
  * Use:		Resizes a memory block.  If there's not enough memory, the
  *		exception @EXC_NOMEM@ is thrown.
+ *
+ *		The @x_reallocv@ function adjusts a block which currently has
+ *		space for @on@ elements each of size @sz@, so that it now has
+ *		enough space for @n@ elements, preserving the initial @min(n,
+ *		on)@ elements.  The @x_realloc@ function is the same, but
+ *		with @sz@ fixed equal to 1, and @n@ and @on@ renamed to @sz@
+ *		and @osz@ for historical reasons.
  */
 
 void *x_realloc(arena *a, void *p, size_t sz, size_t osz)
 {
   p = A_REALLOC(a, p, sz, osz);
-  if (!p)
-    THROW(EXC_NOMEM);
-  return (p);
+    if (!p) THROW(EXC_NOMEM);
+    else return (p);
+}
+
+void *x_reallocv(arena *a, void *p, size_t n, size_t on, size_t sz)
+{
+  p = A_REALLOCV(a, p, n, on, sz);
+    if (!p) THROW(EXC_NOMEM);
+    else return (p);
 }
 
 /* --- @x_free@ --- *
@@ -116,17 +146,20 @@ void (x_free)(arena *a, void *p) { x_free(a, p); }
 
 /*----- Old functions for the standard arena ------------------------------*/
 
-/* --- @xmalloc@ --- *
+/* --- @xmalloc@, @xmallocv@ --- *
  *
- * Arguments:	@size_t sz@ = size of block to allocate
+ * Arguments:	@size_t n@ = number of elements to allocate (for @xmallocv@)
+ *		@size_t sz@ = size of block to allocate
  *
  * Returns:	Pointer to allocated block.
  *
- * Use:		Allocates memory.  If there's not enough memory, the
- *		exception @EXC_NOMEM@ is thrown.
+ * Use:		Allocates memory for @n@ elements each of size @sz@.  For
+ *		@xmalloc@, @n@ is fixed equal to 1.  If there's not enough
+ *		memory, the exception @EXC_NOMEM@ is thrown.
  */
 
 void *(xmalloc)(size_t sz) { return xmalloc(sz); }
+void *(xmallocv)(size_t n, size_t sz) { return xmallocv(n, sz); }
 
 /* --- @xstrdup@ --- *
  *
@@ -141,21 +174,33 @@ void *(xmalloc)(size_t sz) { return xmalloc(sz); }
 
 char *(xstrdup)(const char *s) { return xstrdup(s); }
 
-/* --- @xrealloc@ --- *
+/* --- @xrealloc@, @xreallocv@ --- *
  *
  * Arguments:	@void *p@ = pointer to a block of memory
- *		@size_t sz@ = new size desired for the block
- *		@size_t osz@ = size of the old block
+ *		@size_t n@ = new number of elements (for @xreallocv@)
+ *		@size_t on@ = old  number of elements (for @xreallocv@)
+ *		@size_t sz@ = size of elements (for @xreallocv@) or new
+ *			block size (for @xrealloc@)
+ *		@size_t osz@ = size of the old block (for @xrealloc@)
  *
  * Returns:	Pointer to the resized memory block (which is almost
  *		certainly not in the same place any more).
  *
  * Use:		Resizes a memory block.  If there's not enough memory, the
  *		exception @EXC_NOMEM@ is thrown.
+ *
+ *		The @xreallocv@ function adjusts a block which currently has
+ *		space for @on@ elements each of size @sz@, so that it now has
+ *		enough space for @n@ elements, preserving the initial @min(n,
+ *		on)@ elements.  The @xrealloc@ function is the same, but
+ *		with @sz@ fixed equal to 1, and @n@ and @on@ renamed to @sz@
+ *		and @osz@ for historical reasons.
  */
 
 void *(xrealloc)(void *p, size_t sz, size_t osz)
-{ return xrealloc(p, sz, osz); }
+  { return xrealloc(p, sz, osz); }
+void *(xreallocv)(void *p, size_t n, size_t on, size_t sz)
+  { return xreallocv(p, n, on, sz); }
 
 /* --- @xfree@ --- *
  *